Prosthetic arm is controlled by thought

Posted by Kate Taylor

The world's first thought-controlled robotic arm is due to be implanted in a patient this winter.

"Our technology helps amputees to control an artificial limb, in much the same way as their own biological hand or arm, via the person's own nerves and remaining muscles," says Max Ortiz Catalan of Chalmers University of Technology in Sweden. "This is a huge benefit for both the individual and to society."

Current prostheses are controlled by electrical impulses in the muscles, but have limited functionality as they're difficult to control.

"All movements must by pre-programmed," says Catalan. "It's like having a Ferrari without a steering wheel. Therefore, we have developed a new bidirectional interface with the human body, together with a natural and intuitive control system."

And because today's models have to be attached to the body using a socket tightly fitted on the amputated stump, they're so uncomfortable that only 50 percent of arm amputees are willing to use one at all.

However, Catalan's model is based on the Brånemark titanium implant instead (OPRA Implant System), which anchors the prosthesis directly to the skeleton through what's known as osseointegration.

The researchers plann to implant the electrodes directly on the nerves and remaining muscles, rather than on the skin, meaning the bio-electric signals become much more stable.

The first operations on patients will take place over the next few months.

"By testing the method on a few patients, we can show that the technology works and then hopefully get more grants to continue clinical studies and develop the technology further," says Catalan.

"If the first operations this winter are successful, we will be the first research group in the world to make 'thought-controlled prostheses' a reality for patients to use in their daily activities, and not only inside research labs."